Field of the Invention
The invention relates to a data carrier card, an assembly of at least two data carrier cards and a method of accessing at least one of the data carrier cards of the assembly.
Such data carrier cards are generally known as chip cards. A chip card has standardized dimensions and includes at least one semiconductor circuit disposed in a recess or depression of the card. The chip card has a plurality of terminals, which lie flush with a surface of a main surface area of the card within that surface and away from the edge of the card. Correspondingly complex mechanical devices are necessary in order to make contact with those terminals in a reader. Contact-making may be established by purely mechanical provisions or by using electromechanical effects.
In addition, data carrier cards for data processing devices, in particular personal computers, are known. Those data carriers which are standardized, for example, to the PCMCIA standard, contain one or more semiconductor circuits, which are accessed by the personal computer. Such a PCMCIA card has a terminal strip on one of its edge sides which contains pluggable contacts. The terminal strip is inserted into a corresponding terminal counterpiece in the personal computer.
The conventional data carrier cards are suitable only with reservations for the storage of considerable volumes of data. If a processing device is to access a number of PCMCIA cards, either a card change has to be carried out or else, if a plurality of cards remain inserted simultaneously, there must be a corresponding terminal socket in the processing device for each card. Those terminal devices require relatively considerable volume. That is at odds with the desire to make electronic units ever smaller. In addition, plug connections are complicated to produce and relatively expensive due to their mechanical complexity.
Published European Patent Application 0 231 090 A2, corresponding to U.S. Pat. Nos. 4,909,742 and 4,893,001, discloses an IC card which has a flexible circuit board that is surrounded by insulating plastic and has a multiplicity of electrode terminals on at least one side of the card.
In U.S. Pat. No. 5,289,339, a memory card with symmetrical terminal assignment is described. As a result, connecting of the card to a connector is possible even if the card is inserted the other way round.
Published European Patent Application 0 349 726 A2, corresponding to U.S. Pat. Nos. 5,129,091 and 5,410,714, describes an IC card with a power-saving operating state.
An IC memory card in which many memory chips are stacked on a circuit board is described in Published European Patent Application 0 379 592 A1. The memory chips in that case are interconnected by separate connection lines.